rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P26458/1:b..l P22211/2:b..l rcu: (detected by 0, t=10503 jiffies, g=175217, q=96 ncpus=2) task:syz-executor state:R running task stack:21128 pid:22211 tgid:22211 ppid:22208 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:98 [inline] RIP: 0010:memory_is_nonzero mm/kasan/generic.c:115 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:140 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline] RIP: 0010:kasan_check_range+0x9f/0x2c0 mm/kasan/generic.c:200 Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 41 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 de 01 00 00 49 ff c3 48 ff c3 75 ee e9 21 01 00 00 44 89 dd RSP: 0018:ffffc900050d74d8 EFLAGS: 00000246 RAX: ffffffff81f83c01 RBX: ffffffffffffffff RCX: ffffffff81f83c4b RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffea00010a3634 RBP: 0000000000000001 R08: ffffea00010a3637 R09: 1ffffd40002146c6 R10: dffffc0000000000 R11: fffff940002146c6 R12: 0000000000000001 R13: fffffffffffffffe R14: fffff940002146c7 R15: 1ffffd40002146c6 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_add_unless include/linux/atomic/atomic-instrumented.h:1517 [inline] page_ref_add_unless include/linux/page_ref.h:238 [inline] folio_ref_add_unless include/linux/page_ref.h:248 [inline] folio_try_get+0xdb/0x340 include/linux/page_ref.h:264 find_get_entry mm/filemap.c:2082 [inline] find_lock_entries+0x24f/0xa60 mm/filemap.c:2172 shmem_undo_range+0x254/0x14b0 mm/shmem.c:1102 shmem_truncate_range mm/shmem.c:1232 [inline] shmem_evict_inode+0x272/0xa70 mm/shmem.c:1360 evict+0x504/0x9c0 fs/inode.c:810 __dentry_kill+0x209/0x660 fs/dcache.c:669 dput+0x19f/0x2b0 fs/dcache.c:911 __fput+0x68e/0xa70 fs/file_table.c:476 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3f09f8dc2a RSP: 002b:00007fff45d84bd0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f3f09f8dc2a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007fff45d84c2c R08: 0000000000000000 R09: 00007fff45d84937 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000009f R13: 00005555953f8590 R14: 0000000000000005 R15: 00007fff45d84c80 task:syz.1.4692 state:R running task stack:25624 pid:26458 tgid:26455 ppid:16824 task_flags:0x400040 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:rcu_read_lock include/linux/rcupdate.h:868 [inline] RIP: 0010:class_rcu_constructor include/linux/rcupdate.h:1195 [inline] RIP: 0010:unwind_next_frame+0xd6/0x2390 arch/x86/kernel/unwind_orc.c:479 Code: 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 41 57 e8 be c4 29 00 48 83 c4 08 e8 85 bb d2 09 85 c0 74 3a e8 fc c2 32 00 84 c0 <75> 31 e8 73 bb d2 09 85 c0 74 28 80 3d 28 39 f3 0d 00 75 1f c6 05 RSP: 0018:ffffc9000e066d38 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffffffff8203e037 RCX: 060308e048098000 RDX: 0000000000000000 RSI: ffffffff8bbf0740 RDI: ffffffff8bbf0700 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff81738d25 R10: dffffc0000000000 R11: ffffffff81ac2f50 R12: 1ffff92001c0cdc1 R13: ffffc9000e066e40 R14: ffffc9000e066e08 R15: ffffffff81738d25 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:332 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2435 shmem_alloc_folio mm/shmem.c:1871 [inline] shmem_alloc_and_add_folio+0x447/0xf60 mm/shmem.c:1910 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2533 shmem_fault+0x179/0x390 mm/shmem.c:2734 __do_fault+0x138/0x390 mm/memory.c:5280 do_read_fault mm/memory.c:5698 [inline] do_fault mm/memory.c:5832 [inline] do_pte_missing mm/memory.c:4361 [inline] handle_pte_fault mm/memory.c:6177 [inline] __handle_mm_fault+0x35e3/0x5400 mm/memory.c:6318 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6487 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x165c/0x2a00 mm/gup.c:1428 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860 __mm_populate+0x24c/0x380 mm/gup.c:1963 mm_populate include/linux/mm.h:3471 [inline] vm_mmap_pgoff+0x387/0x4d0 mm/util.c:586 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff9a358efc9 RSP: 002b:00007ff9a4481038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007ff9a37e6090 RCX: 00007ff9a358efc9 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007ff9a3611f91 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff9a37e6128 R14: 00007ff9a37e6090 R15: 00007ffcd9631658 rcu: rcu_preempt kthread starved for 8002 jiffies! g175217 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:25600 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 5e 03 ca f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d f3 f1 21 00 f3 0f 1e fa fb f4 33 03 ca f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6 RAX: 68db59d3c3ef1100 RBX: ffffffff81967bf7 RCX: 68db59d3c3ef1100 RDX: 0000000000000001 RSI: ffffffff8d70d450 RDI: ffffffff8bbf0760 RBP: ffffffff8dc07ea8 R08: ffff8880b8832fdb R09: 1ffff110171065fb R10: dffffc0000000000 R11: ffffed10171065fc R12: ffffffff8f7cdc70 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92a40 FS: 0000000000000000(0000) GS:ffff88812613d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555584c305c8 CR3: 0000000078a6e000 CR4: 0000000000350ef0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3ae/0x410 init/main.c:1111 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147